Question 1

Which of the following statements best explains why the blending hypothesis of inheritance was rejected?

Accepted Answer

It could not explain how traits that disappear in one generation can reappear in later generations.

Question 2

A true-breeding purple-flowered pea plant is crossed with a true-breeding white-flowered pea plant. All offspring in the F1 generation have purple flowers. What is the genotype of the F1 generation?

Accepted Answer

$$Pp$$

Question 3

According to Mendel’s law of segregation, what happens to alleles during gamete formation?

Accepted Answer

Allele pairs separate so that each gamete carries only one allele for each gene.

Question 4

In a dihybrid cross between two individuals heterozygous for both seed color (Yy) and seed shape (Rr), what is the expected phenotypic ratio in the F2 generation according to Mendel’s law of independent assortment?

Accepted Answer

$$9:3:3:1$$

Question 5

A testcross is performed between a black Labrador of unknown genotype and a chocolate Labrador (bb). If all offspring are black, what is the genotype of the black Labrador?

Accepted Answer

$$BB$$

Question 6

A couple, both carriers for cystic fibrosis (genotype $$Ff$$), want to know the probability that their child will have cystic fibrosis. What is the probability?

Accepted Answer

$$\frac{1}{4}$$

Question 7

Which of the following best describes incomplete dominance?

Accepted Answer

The phenotype of heterozygotes is intermediate between the phenotypes of individuals homozygous for either allele.

Question 8

A woman with type A blood ($$I^A I^i) $$and a man with type B blood ($$I^B I^i) $$have a child. Which blood type is NOT possible for their child?

Accepted Answer

All blood types are possible for this cross.

Question 9

Sickle-cell disease is an example of pleiotropy because:

Accepted Answer

A single gene affects multiple phenotypic traits.

Question 10

Human skin color is an example of polygenic inheritance. If two parents with genotype $$AaBbCc$$ have a child, what is the probability that the child will have the genotype $$AABbcc$$?

Accepted Answer

$$\frac{1}{64}$$

Question 11

Which phase of meiosis is the physical basis for Mendel’s law of segregation?

Accepted Answer

Anaphase I

Question 12

Linked genes do not follow Mendel’s law of independent assortment because:

Accepted Answer

They are located close together on the same chromosome and tend to be inherited together.

Question 13

A white-eyed female fruit fly (XrXr) is crossed with a red-eyed male (XRY). What is the expected phenotype of their offspring?

Accepted Answer

All daughters will be red-eyed, all sons will be white-eyed.

Question 14

Which of the following is a real-world example of a trait influenced by both genetic and environmental factors?

Accepted Answer

The sex of some reptiles, which is determined by incubation temperature.

Question 15

A geneticist finds that two genes have a recombination frequency of 9%. What does this indicate about their location?

Accepted Answer

They are relatively close together on the same chromosome.

Question 16

Which of the following best describes the chromosomal theory of inheritance?

Accepted Answer

Genes occupy specific loci on chromosomes, and chromosomes undergo segregation and independent assortment during meiosis.

Question 17

A woman who is a carrier for hemophilia (an X-linked recessive disorder) and a normal man have a son. What is the probability that their son will have hemophilia?

Accepted Answer

$$\frac{1}{2}$$

Question 18

Which of the following is a benefit of chorionic villus sampling (CVS) compared to amniocentesis?

Accepted Answer

Results can be obtained earlier in pregnancy.

Question 19

Why was Mendel able to ignore environmental influences in his pea plant experiments?

Accepted Answer

He used controlled conditions that minimized environmental variation.

Question 20

Which of the following best explains why the sickle-cell allele is maintained at a relatively high frequency in some human populations?

Accepted Answer

Carriers have increased resistance to malaria.

Patterns of Inheritance: Mendelian Genetics and Beyond

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